This rat poison is wreaking havoc on Australian ecosystems, so why are North Shore councils still using it?

Despite being legal in Australia, SGAR poisons can kill native wildlife by spreading through food chains.

In the pursuit of eliminating rats from our urban areas, local councils may be inadvertently poisoning and killing owls, birds, possums and lizards on the North Shore.

Second-Generation Anticoagulant Rodenticide (SGAR) is a type of rat poison readily available at retailers such as Woolworths and Bunnings. 

Currently, multiple councils on and around the North Shore — such as Ku-ring-gai and North Sydney — use SGAR as part of their rodent control program. 

While Ku-ring-gai Council says it uses the substance “very sparingly” and “always in locations that are inaccessible to other animals”, it is not wildlife consuming the poison at the source that is the issue, but poisons entering the larger food chain. 

Zoologist Dr Renae Charalambous told the Lorikeet rats are a “common food source” for many native species. 

How does it kill? SGAR causes internal bleeding and it takes a number of days for rodents to die, during which time they become easy targets for predators, and this leads to the poison spreading through the food chain. 

Dr Charalambous says this kills native wildlife, predominantly birds like tawny frogmouths, powerful owls, magpies and kookaburras, but also marsupials and reptiles. 

A 2021 study from Birdlife Australia analysing the livers of dead powerful owls found that 37 of 38 samples contained an anticoagulant rodenticide (AR).

Some councils, such as the City of Ryde, have moved to ban the poison in council-run and outsourced pest control. North Sydney Council is preparing a report on alternative methods of pest control, and a plan for phasing out SGAR products.

Amazon no longer sells SGARs on its Australian website. In the U.S., Canada and the European Union, SGAR has either been banned or limited to professional use. 

Change on the way? A review released in December by the Australian Pesticides and Veterinary Medicines Authority (APVMA) recommended tighter restrictions be placed on SGAR products. The proposition is on public exhibition until March. APVMA is the federal  regulator of agricultural and veterinary chemical products. 

Alternatives: Animal welfare group Humane World for Animals urges non-lethal strategies for rodent control, such as rodent-proofing homes with wire mesh and ensuring food waste is not left in the open. 

While generally advising against the use of poisons, Birdlife Australia says safer alternatives exist, such as sodium chloride-based poisons like Ratsak Naturals.

Thumbnail: Joshua J. Cotten via Unsplash, Birdlife Australia